RockMelt, the "social" browser, which is really a Facebook browser, just raised $30 million more from Andreessen Horowitz, Khosla Ventures and Accel Partners.

Andreessen Horowitz Partner Ben Horowitz explains the move on his blog: the browser really matters and hasn't evolved that much in the past 15 years; people do change browsers; people who use Rockmelt are really engaged. Also the founders of Rockmelt are a bunch of ex-Netscape rockstars.